Ferdinand, Cisneros and Isabella

At the end While fernando(Ferdinand) is on his deathbed, while his young wife Germaine sits by his bed, he has a vision of his dead wife and queen Isabella, who smiles as if to welcome him to the next world.
But I thought also that it was a complicit smile, as if from beyond the grave they had managed to ensure Phillip the handsome did not take over their empire. Instead it would be their grandson Charles as Isabella had willed it. But Charles like his father was a foreigner and within 4 years Spain would be on the verge of bankruptcy and Revolution. Was it worth it?